GnuPG public key vulnerability?

Jonathan Millican gnupg at
Wed Nov 1 04:05:17 CET 2017

Hi Murphy,

This email refers to the ROCA vulnerability (
public/papers/rsa_ccs17), which affects a number of hardware devices
including some versions of the Yubikey 4-nano (
keycheck/). I believe Yubico are offering to replace affected Yubikeys.

One aspect of this vulnerability is that RSA public keys can be very easily
checked to determine if they are vulnerable - so at Facebook, we checked
the public keys that have been uploaded to people's profiles, and notified
people whose keys are affected. Unfortunately it seems like you were one of
the unlucky ones! Details here:

Hope that helps,

On 1 November 2017 at 00:10, murphy <mac3iii at> wrote:

> I got a signed notification from facebook (good signature, enigmail)
> that claims my GnuPG generated public key has a "recently disclosed
> vulnerability".  This is the full text:
> We have detected that the OpenPGP key on your Facebook profile may be
> susceptible to attacks due to a recently disclosed vulnerability.  We
> recommend that you revoke and replace your public key immediately to
> minimize the risk to your encrypted communications.  You can update your
> public key by visiting your Security and Login settings.  To help reduce
> the risk of your key being attacked, we have set the privacy of your
> potentially vulnerable public key on your profile to "Only Me" to limit
> further distribution.  We will continue to encrypt your notification
> emails using this OpenPGP public key.
> This is doubly weird since the private/public key was generated on a
> Yubikey-4 nano and it is safe at home.  Does anyone know what this may
> be about?
> Facebook public key (it is valid, see:
> securing-email-communications-from-facebook/1611941762379302/):
> pub   rsa4096 2015-05-17 [SC] [expires: 2018-05-17]
>          31A70953D8D590BA1FAB37762F3898CEDEE958CF
> uid           [  full  ] Facebook, Inc.
> sub   rsa4096 2017-07-24 [S] [expires: 2018-02-19]
> My public key is uploaded to keyservers and is:
> pub   rsa4096 2016-10-17 [SC] [expires: 2018-10-17]
>          D89A29A3E1DA59DFBF516EA73E450D1BCF78C26B
> uid           [ultimate] orange
> uid           [ultimate] Murphy Chesney (facebook communication)
> <mac3iii at>
> sub   rsa4096 2016-10-17 [A] [expires: 2018-10-17]
> sub   rsa2048 2016-10-17 [E] [expires: 2018-10-17]
> Murphy
> _______________________________________________
> Gnupg-users mailing list
> Gnupg-users at
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